shmem: respect MAX_LFS_FILESIZE
commitcaefba1740d8016e6dfe8fda84f85bdcb8f8c85d
authorHugh Dickins <hugh@veritas.com>
Mon, 13 Apr 2009 21:40:12 +0000 (13 14:40 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Mon, 13 Apr 2009 22:04:33 +0000 (13 15:04 -0700)
tree78a74e7a42b94ac83c736849c46767b7efeb8ef1
parent61609d01cbb3ab865c8cccaf85e6837c47096480
shmem: respect MAX_LFS_FILESIZE

SHMEM_MAX_BYTES was derived from the maximum size of its triple-indirect
swap vector, forgetting to take the MAX_LFS_FILESIZE limit into account.
Never mind 256kB pages, even 8kB pages on 32-bit kernels allowed files to
grow slightly bigger than that supposed maximum.

Fix this by using the min of both (at build time not run time).  And it
happens that this calculation is good as far as 8MB pages on 32-bit or
16MB pages on 64-bit: though SHMSWP_MAX_INDEX gets truncated before that,
it's truncated to such large numbers that we don't need to care.

[akpm@linux-foundation.org: it needs pagemap.h]
[akpm@linux-foundation.org: fix sparc64 min() warnings]
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Yuri Tikhonov <yur@emcraft.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/shmem.c